64 EXPLANATION OF THE PLATES. 



Pig. 10. Inferior view of the last median phalanx. 



Fig. 11. Carpal surface of the annular metacarpal boue. The three divisions of the surface from 

 right to left of the figure, articulate with the auricular metacarpal bone, the unciform bone, and the 

 median metacarpal bone. 



Fig. 12. Outer view of the annular metacarpal boue. 



Fig. 13. Carpal surface of the median metacarpal bone. The left upper lobe articulates with the 

 index metacarpal, trapezoid, and magnum bones ; the lower lobe articulates with the os magnum ; and 

 the right upper lobe articulates with the latter and with the unciform bone. 



Fig. 14. Inner view of the proximal end of the median metacarpal bone, with the articular surface 

 for the annular metacarpal bone. 



Fig. 15. Inner view of the index metacarpal bone. The articular facet at the upper part of the 

 proximal extremity is for the median metacarpal bone. 



Fig. 16. Carpal surface of the index metacarpal bone. 



Fig. 11. Outer view of the proximal extremity of the index metacarpal bone, with the articular sur- 

 face for the first metacarpal bone. 



Fig. 18. Dorsal view of the left auricular metacarpal bone. 



Fig. 19. Outer view of the same specimen. The articular facet at the proximal end is for the annular 

 metacarpal bone. 



Fig. 20. Lateral view of the ungual phalanx of the thumb. 



PLATE XI. 



Megalonyx Jeffersonii. All the figures are one-third the diameter of nature, and are from speci- 

 mens in Dr. Owen's collection. 



Fig. 1. Front view of the left femur. 

 Fig. 2. Back view of the left femur. 

 Fig. 3. Distal view of the left femur. 

 Fig. 4. Proximal view of the left tibia. 

 Fig. 5. Outer view of the patella. 

 Fig. 6. Inner view of the patella. 



PLATE XII. 



Megalonyx Jeffeesonh. All the figures are one-third the diameter of nature, and are from speci- 

 mens in Dr. Owen's collection. 



Fig. 1. Front view of the left tibia. 



Fig. 2. Outer view of the left tibia. 



Fig. 8. Back view of the left tibia. 



Fig. 4. Distal view of the left tibia, a, fibular articulation ; b, articular surface for the astragalus. 



Fig. 5. Outer view of the left os calcis. 



Fig. 6. Anterior view of the left os calcis. a, h, articular surfaces for the astragalus ; c, articular 

 surface for the cuboid bone. 



Fig. Y. Upper view of the left astragalus. The large articular surface is for the tibia ; the angular 

 fossa receives a short process of the latter ; and the concave fossa of the apophysis articulates with the 

 scaphoid bone. 



Fig. 8. Inferior view of the astragalus. The upper broad articular surface is for the calcaneum; and 

 the articular surface, seen on the apophysis, joins, from right to left and downward, the calcaneum, and 

 the cuboid and scaphoid bones. 



Fig. 9. Anterior view of the astragalus, with the articular surface for the scaphoid bone. 



Fig. 10. Outer view of the astragalus, a, articular surface for the fibula ; h, articular surface for the 

 cuboid bone. 



